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Wastes with Fuel Value

Environmental Engineering · FE Reference Handbook section

Environmental Engineering
0 formulas
10 exam-style examples
~45 min
All Environmental Engineering lectures

Handbook notes for this section

Definitions and conditions exactly as the handbook states them.

  • Oily waste and residue 18,000 41,940

Core formulas for this FE topic

Definitions, applicability, units, assumptions and worked examples for each relation.

This section is conceptual; there are no equations to memorise.

Worked exam-style examples

The four ways this section is written on the real exam — thoughts first, then equations, then substitution.

Example 1
Wastes with Fuel Value — solve for higher heating value of waste — Wastes with Fuel Value

wastes with fuel value heating value estimate for waste-to-energy design Given fraction carbon (C) = 0.4070; fraction hydrogen (H) = 0.0800; fraction oxygen (O) = 0.2980; fraction sulfur (S) = 0.0049, determine the higher heating value of waste (HHV) in MJ/kg.

Given

  • fractioncarbon(C)=0.4070fraction carbon (C) = 0.4070
  • fractionhydrogen(H)=0.0800fraction hydrogen (H) = 0.0800
  • fractionoxygen(O)=0.2980fraction oxygen (O) = 0.2980
  • fractionsulfur(S)=0.0049fraction sulfur (S) = 0.0049

Find

higher heating value of waste (HHV), in MJ/kg

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except HHV is given, so isolate HHV symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for HHV:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87C+143.34\left(H-\dfrac{O}{8}\right)+9.4S
  3. Step 3 — List the givens: fraction carbon (C) = 0.4070, fraction hydrogen (H) = 0.0800, fraction oxygen (O) = 0.2980, fraction sulfur (S) = 0.0049.

  4. Step 4 — Substitute the given values:

    HHV=45.870.4070+143.34(0.0800−0.29808)+9.40.0049HHV = 45.870.4070+143.34\left(0.0800-\dfrac{0.2980}{8}\right)+9.40.0049
  5. Step 5 — Evaluate:

    HHV=24.8429 MJ/kgHHV = 24.8429\ \text{MJ/kg}
  6. Step 6 — Check: returning HHV = 24.8429 MJ/kg to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
HHV=24.8429 MJ/kgHHV = 24.8429\ \text{MJ/kg}

Why the other options are there

  • 49.6859 — kept a factor of two that cancels in the correct rearrangement.
  • 12.4215 — dropped that same factor in the other direction.
  • 27.3272 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 2
Wastes with Fuel Value — solve for fraction carbon — Wastes with Fuel Value (2)

municipal solid wastes with fuel value characterized by elemental analysis Given fraction hydrogen (H) = 0.0380; fraction oxygen (O) = 0.2880; fraction sulfur (S) = 0.0191; higher heating value of waste (HHV) = 14.6800 MJ/kg, determine the fraction carbon (C).

Given

  • fractionhydrogen(H)=0.0380fraction hydrogen (H) = 0.0380
  • fractionoxygen(O)=0.2880fraction oxygen (O) = 0.2880
  • fractionsulfur(S)=0.0191fraction sulfur (S) = 0.0191
  • higherheatingvalueofwaste(HHV)=14.6800MJ/kghigher heating value of waste (HHV) = 14.6800 MJ/kg

Find

fraction carbon (C)

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except C is given, so isolate C symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for C:

    C=HHV−143.34(H−O8)−9.4S45.87C = \dfrac{HHV-143.34\left(H-\dfrac{O}{8}\right)-9.4S}{45.87}
  3. Step 3 — List the givens: fraction hydrogen (H) = 0.0380, fraction oxygen (O) = 0.2880, fraction sulfur (S) = 0.0191, higher heating value of waste (HHV) = 14.6800 MJ/kg.

  4. Step 4 — Substitute the given values:

    C=14.6800−143.34(0.0380−0.28808)−9.40.019145.87C = \dfrac{14.6800-143.34\left(0.0380-\dfrac{0.2880}{8}\right)-9.40.0191}{45.87}
  5. Step 5 — Evaluate:

    C=0.3099C = 0.3099
  6. Step 6 — Check: returning C = 0.3099 to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
C=0.3099C = 0.3099

Why the other options are there

  • 0.6197 — kept a factor of two that cancels in the correct rearrangement.
  • 0.1549 — dropped that same factor in the other direction.
  • 0.3409 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 3
Wastes with Fuel Value — solve for higher heating value of waste (case 2) — Wastes with Fuel Value (3)

wastes with fuel value HHV computed from carbon, hydrogen, oxygen, sulfur fractions Given fraction carbon (C) = 0.2110; fraction hydrogen (H) = 0.0990; fraction oxygen (O) = 0.2920; fraction sulfur (S) = 0.0143, determine the higher heating value of waste (HHV) in MJ/kg.

Given

  • fractioncarbon(C)=0.2110fraction carbon (C) = 0.2110
  • fractionhydrogen(H)=0.0990fraction hydrogen (H) = 0.0990
  • fractionoxygen(O)=0.2920fraction oxygen (O) = 0.2920
  • fractionsulfur(S)=0.0143fraction sulfur (S) = 0.0143

Find

higher heating value of waste (HHV), in MJ/kg

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except HHV is given, so isolate HHV symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for HHV:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87C+143.34\left(H-\dfrac{O}{8}\right)+9.4S
  3. Step 3 — List the givens: fraction carbon (C) = 0.2110, fraction hydrogen (H) = 0.0990, fraction oxygen (O) = 0.2920, fraction sulfur (S) = 0.0143.

  4. Step 4 — Substitute the given values:

    HHV=45.870.2110+143.34(0.0990−0.29208)+9.40.0143HHV = 45.870.2110+143.34\left(0.0990-\dfrac{0.2920}{8}\right)+9.40.0143
  5. Step 5 — Evaluate:

    HHV=18.7717 MJ/kgHHV = 18.7717\ \text{MJ/kg}
  6. Step 6 — Check: returning HHV = 18.7717 MJ/kg to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
HHV=18.7717 MJ/kgHHV = 18.7717\ \text{MJ/kg}

Why the other options are there

  • 37.5435 — kept a factor of two that cancels in the correct rearrangement.
  • 9.3859 — dropped that same factor in the other direction.
  • 20.6489 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 4
Wastes with Fuel Value — solve for fraction carbon (case 2) — Wastes with Fuel Value (4)

wastes with fuel value heating value estimate for waste-to-energy design Given fraction hydrogen (H) = 0.0450; fraction oxygen (O) = 0.1810; fraction sulfur (S) = 0.0053; higher heating value of waste (HHV) = 5.1300 MJ/kg, determine the fraction carbon (C).

Given

  • fractionhydrogen(H)=0.0450fraction hydrogen (H) = 0.0450
  • fractionoxygen(O)=0.1810fraction oxygen (O) = 0.1810
  • fractionsulfur(S)=0.0053fraction sulfur (S) = 0.0053
  • higherheatingvalueofwaste(HHV)=5.1300MJ/kghigher heating value of waste (HHV) = 5.1300 MJ/kg

Find

fraction carbon (C)

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except C is given, so isolate C symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for C:

    C=HHV−143.34(H−O8)−9.4S45.87C = \dfrac{HHV-143.34\left(H-\dfrac{O}{8}\right)-9.4S}{45.87}
  3. Step 3 — List the givens: fraction hydrogen (H) = 0.0450, fraction oxygen (O) = 0.1810, fraction sulfur (S) = 0.0053, higher heating value of waste (HHV) = 5.1300 MJ/kg.

  4. Step 4 — Substitute the given values:

    C=5.1300−143.34(0.0450−0.18108)−9.40.005345.87C = \dfrac{5.1300-143.34\left(0.0450-\dfrac{0.1810}{8}\right)-9.40.0053}{45.87}
  5. Step 5 — Evaluate:

    C=0.0408C = 0.0408
  6. Step 6 — Check: returning C = 0.0408 to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
C=0.0408C = 0.0408

Why the other options are there

  • 0.0817 — kept a factor of two that cancels in the correct rearrangement.
  • 0.0204 — dropped that same factor in the other direction.
  • 0.0449 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 5
Wastes with Fuel Value — solve for higher heating value of waste (case 3) — Wastes with Fuel Value (5)

municipal solid wastes with fuel value characterized by elemental analysis Given fraction carbon (C) = 0.2500; fraction hydrogen (H) = 0.0720; fraction oxygen (O) = 0.1690; fraction sulfur (S) = 0.0113, determine the higher heating value of waste (HHV) in MJ/kg.

Given

  • fractioncarbon(C)=0.2500fraction carbon (C) = 0.2500
  • fractionhydrogen(H)=0.0720fraction hydrogen (H) = 0.0720
  • fractionoxygen(O)=0.1690fraction oxygen (O) = 0.1690
  • fractionsulfur(S)=0.0113fraction sulfur (S) = 0.0113

Find

higher heating value of waste (HHV), in MJ/kg

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except HHV is given, so isolate HHV symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for HHV:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87C+143.34\left(H-\dfrac{O}{8}\right)+9.4S
  3. Step 3 — List the givens: fraction carbon (C) = 0.2500, fraction hydrogen (H) = 0.0720, fraction oxygen (O) = 0.1690, fraction sulfur (S) = 0.0113.

  4. Step 4 — Substitute the given values:

    HHV=45.870.2500+143.34(0.0720−0.16908)+9.40.0113HHV = 45.870.2500+143.34\left(0.0720-\dfrac{0.1690}{8}\right)+9.40.0113
  5. Step 5 — Evaluate:

    HHV=18.8661 MJ/kgHHV = 18.8661\ \text{MJ/kg}
  6. Step 6 — Check: returning HHV = 18.8661 MJ/kg to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
HHV=18.8661 MJ/kgHHV = 18.8661\ \text{MJ/kg}

Why the other options are there

  • 37.7323 — kept a factor of two that cancels in the correct rearrangement.
  • 9.4331 — dropped that same factor in the other direction.
  • 20.7528 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 6
Wastes with Fuel Value — solve for fraction carbon (case 3) — Wastes with Fuel Value (6)

wastes with fuel value HHV computed from carbon, hydrogen, oxygen, sulfur fractions Given fraction hydrogen (H) = 0.0820; fraction oxygen (O) = 0.1820; fraction sulfur (S) = 0.0099; higher heating value of waste (HHV) = 13.0400 MJ/kg, determine the fraction carbon (C).

Given

  • fractionhydrogen(H)=0.0820fraction hydrogen (H) = 0.0820
  • fractionoxygen(O)=0.1820fraction oxygen (O) = 0.1820
  • fractionsulfur(S)=0.0099fraction sulfur (S) = 0.0099
  • higherheatingvalueofwaste(HHV)=13.0400MJ/kghigher heating value of waste (HHV) = 13.0400 MJ/kg

Find

fraction carbon (C)

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except C is given, so isolate C symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for C:

    C=HHV−143.34(H−O8)−9.4S45.87C = \dfrac{HHV-143.34\left(H-\dfrac{O}{8}\right)-9.4S}{45.87}
  3. Step 3 — List the givens: fraction hydrogen (H) = 0.0820, fraction oxygen (O) = 0.1820, fraction sulfur (S) = 0.0099, higher heating value of waste (HHV) = 13.0400 MJ/kg.

  4. Step 4 — Substitute the given values:

    C=13.0400−143.34(0.0820−0.18208)−9.40.009945.87C = \dfrac{13.0400-143.34\left(0.0820-\dfrac{0.1820}{8}\right)-9.40.0099}{45.87}
  5. Step 5 — Evaluate:

    C=0.0971C = 0.0971
  6. Step 6 — Check: returning C = 0.0971 to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
C=0.0971C = 0.0971

Why the other options are there

  • 0.1942 — kept a factor of two that cancels in the correct rearrangement.
  • 0.0486 — dropped that same factor in the other direction.
  • 0.1068 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 7
Wastes with Fuel Value — solve for higher heating value of waste (case 4) — Wastes with Fuel Value (7)

wastes with fuel value heating value estimate for waste-to-energy design Given fraction carbon (C) = 0.4020; fraction hydrogen (H) = 0.0270; fraction oxygen (O) = 0.2260; fraction sulfur (S) = 0.0098, determine the higher heating value of waste (HHV) in MJ/kg.

Given

  • fractioncarbon(C)=0.4020fraction carbon (C) = 0.4020
  • fractionhydrogen(H)=0.0270fraction hydrogen (H) = 0.0270
  • fractionoxygen(O)=0.2260fraction oxygen (O) = 0.2260
  • fractionsulfur(S)=0.0098fraction sulfur (S) = 0.0098

Find

higher heating value of waste (HHV), in MJ/kg

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except HHV is given, so isolate HHV symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for HHV:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87C+143.34\left(H-\dfrac{O}{8}\right)+9.4S
  3. Step 3 — List the givens: fraction carbon (C) = 0.4020, fraction hydrogen (H) = 0.0270, fraction oxygen (O) = 0.2260, fraction sulfur (S) = 0.0098.

  4. Step 4 — Substitute the given values:

    HHV=45.870.4020+143.34(0.0270−0.22608)+9.40.0098HHV = 45.870.4020+143.34\left(0.0270-\dfrac{0.2260}{8}\right)+9.40.0098
  5. Step 5 — Evaluate:

    HHV=18.3527 MJ/kgHHV = 18.3527\ \text{MJ/kg}
  6. Step 6 — Check: returning HHV = 18.3527 MJ/kg to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
HHV=18.3527 MJ/kgHHV = 18.3527\ \text{MJ/kg}

Why the other options are there

  • 36.7054 — kept a factor of two that cancels in the correct rearrangement.
  • 9.1763 — dropped that same factor in the other direction.
  • 20.1880 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 8
Wastes with Fuel Value — solve for fraction carbon (case 4) — Wastes with Fuel Value (8)

municipal solid wastes with fuel value characterized by elemental analysis Given fraction hydrogen (H) = 0.0720; fraction oxygen (O) = 0.3400; fraction sulfur (S) = 0.0045; higher heating value of waste (HHV) = 17.2000 MJ/kg, determine the fraction carbon (C).

Given

  • fractionhydrogen(H)=0.0720fraction hydrogen (H) = 0.0720
  • fractionoxygen(O)=0.3400fraction oxygen (O) = 0.3400
  • fractionsulfur(S)=0.0045fraction sulfur (S) = 0.0045
  • higherheatingvalueofwaste(HHV)=17.2000MJ/kghigher heating value of waste (HHV) = 17.2000 MJ/kg

Find

fraction carbon (C)

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except C is given, so isolate C symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for C:

    C=HHV−143.34(H−O8)−9.4S45.87C = \dfrac{HHV-143.34\left(H-\dfrac{O}{8}\right)-9.4S}{45.87}
  3. Step 3 — List the givens: fraction hydrogen (H) = 0.0720, fraction oxygen (O) = 0.3400, fraction sulfur (S) = 0.0045, higher heating value of waste (HHV) = 17.2000 MJ/kg.

  4. Step 4 — Substitute the given values:

    C=17.2000−143.34(0.0720−0.34008)−9.40.004545.87C = \dfrac{17.2000-143.34\left(0.0720-\dfrac{0.3400}{8}\right)-9.40.0045}{45.87}
  5. Step 5 — Evaluate:

    C=0.2819C = 0.2819
  6. Step 6 — Check: returning C = 0.2819 to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
C=0.2819C = 0.2819

Why the other options are there

  • 0.5637 — kept a factor of two that cancels in the correct rearrangement.
  • 0.1409 — dropped that same factor in the other direction.
  • 0.3101 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 9
Wastes with Fuel Value — solve for higher heating value of waste (case 5) — Wastes with Fuel Value (9)

wastes with fuel value HHV computed from carbon, hydrogen, oxygen, sulfur fractions Given fraction carbon (C) = 0.4310; fraction hydrogen (H) = 0.0210; fraction oxygen (O) = 0.2840; fraction sulfur (S) = 0.0063, determine the higher heating value of waste (HHV) in MJ/kg.

Given

  • fractioncarbon(C)=0.4310fraction carbon (C) = 0.4310
  • fractionhydrogen(H)=0.0210fraction hydrogen (H) = 0.0210
  • fractionoxygen(O)=0.2840fraction oxygen (O) = 0.2840
  • fractionsulfur(S)=0.0063fraction sulfur (S) = 0.0063

Find

higher heating value of waste (HHV), in MJ/kg

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except HHV is given, so isolate HHV symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for HHV:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87C+143.34\left(H-\dfrac{O}{8}\right)+9.4S
  3. Step 3 — List the givens: fraction carbon (C) = 0.4310, fraction hydrogen (H) = 0.0210, fraction oxygen (O) = 0.2840, fraction sulfur (S) = 0.0063.

  4. Step 4 — Substitute the given values:

    HHV=45.870.4310+143.34(0.0210−0.28408)+9.40.0063HHV = 45.870.4310+143.34\left(0.0210-\dfrac{0.2840}{8}\right)+9.40.0063
  5. Step 5 — Evaluate:

    HHV=17.7508 MJ/kgHHV = 17.7508\ \text{MJ/kg}
  6. Step 6 — Check: returning HHV = 17.7508 MJ/kg to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
HHV=17.7508 MJ/kgHHV = 17.7508\ \text{MJ/kg}

Why the other options are there

  • 35.5015 — kept a factor of two that cancels in the correct rearrangement.
  • 8.8754 — dropped that same factor in the other direction.
  • 19.5258 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

Example 10
Wastes with Fuel Value — solve for fraction carbon (case 5) — Wastes with Fuel Value (10)

wastes with fuel value heating value estimate for waste-to-energy design Given fraction hydrogen (H) = 0.0930; fraction oxygen (O) = 0.3040; fraction sulfur (S) = 0.0043; higher heating value of waste (HHV) = 32.4200 MJ/kg, determine the fraction carbon (C).

Given

  • fractionhydrogen(H)=0.0930fraction hydrogen (H) = 0.0930
  • fractionoxygen(O)=0.3040fraction oxygen (O) = 0.3040
  • fractionsulfur(S)=0.0043fraction sulfur (S) = 0.0043
  • higherheatingvalueofwaste(HHV)=32.4200MJ/kghigher heating value of waste (HHV) = 32.4200 MJ/kg

Find

fraction carbon (C)

Start with the thinking

  • The governing relation printed in this handbook section is Wastes with Fuel Value.
  • Everything except C is given, so isolate C symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Wastes with fuel value are characterized by a Dulong-type formula estimating higher heating value from elemental composition.

Step-by-step solution

  1. Step 1 — State the governing relation:

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S
  2. Step 2 — Rearrange symbolically for C:

    C=HHV−143.34(H−O8)−9.4S45.87C = \dfrac{HHV-143.34\left(H-\dfrac{O}{8}\right)-9.4S}{45.87}
  3. Step 3 — List the givens: fraction hydrogen (H) = 0.0930, fraction oxygen (O) = 0.3040, fraction sulfur (S) = 0.0043, higher heating value of waste (HHV) = 32.4200 MJ/kg.

  4. Step 4 — Substitute the given values:

    C=32.4200−143.34(0.0930−0.30408)−9.40.004345.87C = \dfrac{32.4200-143.34\left(0.0930-\dfrac{0.3040}{8}\right)-9.40.0043}{45.87}
  5. Step 5 — Evaluate:

    C=0.5340C = 0.5340
  6. Step 6 — Check: returning C = 0.5340 to

    HHV=45.87C+143.34(H−O8)+9.4SHHV = 45.87 C + 143.34\left(H - \dfrac{O}{8}\right) + 9.4 S

    reproduces the given quantities, and both sides carry the same units.

Answer:
C=0.5340C = 0.5340

Why the other options are there

  • 1.0681 — kept a factor of two that cancels in the correct rearrangement.
  • 0.2670 — dropped that same factor in the other direction.
  • 0.5874 — rounded an intermediate value before the final step.

Reference: FE Handbook — Wastes with Fuel Value (Dulong formula)

© 2026 Dr. Steve Efe. Civil Engineering Capstone Studio. All rights reserved.